Telephone system with several terminals on a single line

Abstract

In a telephone system, several telephone terminals are connected to a single telephone line including several telephone interface circuits (6, 7, 8), each interface circuit being energized by ringing signals appearing on the line and being arranged between the telephone line (3) and one of the telephone terminals (13, 14, 15, 16), the ring of which is disconnected from the line. Each interface circuit comprises a circuit (26) for counting ringing signals and picking up the line, this first circuit receiving at the input the ringing signals appearing on the line (L1-L2) during a telephone call, and counting a predetermined number of these ringing signals, then picking up the line by a relay (27) at the moment the last ringing signal counted stops. The system is powered only by the signals on the telephone line.

Dependencies are inferred from the claim text.